Elastin is one of the major structural proteins in arterial vessels. A theme related to the current view of the atherosclerotic process is that the initiation of plaque formation is caused by focal breaks in the elastic fibers comprising the internal elastic lamina of vessel walls. Much of the effort in this proposal is directed at investigations on factors which have bearing on elastin synthesis (atherosclerosis induced by diet, hypertension, endocrine hormones, developmental changes). A further component of the work is directed at determining long-term changes in elastic fibers, since they are comprised of proteins that undergo relatively little biological turnover. Elastin is synthesized in relationship to organ development at very early stages in life and once it is synthesized, its degradation and turnover are limited, except in disease processes. This project seeks to determine the degree to which modifications in elastin maturation or synthesis occur in conditions such as experimental atherosclerosis, hypertension, and nutrient deficiencies.